1. Field of the Invention
Embodiments relate managing early media for communication sessions established via the session initiation protocol (SIP).
2. Description of the Related Art
Wireless communication systems have developed through various generations, including a first-generation analog wireless phone service (1G), a second-generation (2G) digital wireless phone service (including interim 2.5G and 2.75G networks) and a third-generation (3G) high speed data, Internet-capable wireless service. There are presently many different types of wireless communication systems in use, including Cellular and Personal Communications Service (PCS) systems. Examples of known cellular systems include the cellular Analog Advanced Mobile Phone System (AMPS), and digital cellular systems based on Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), the Global System for Mobile access (GSM) variation of TDMA, and newer hybrid digital communication systems using both TDMA and CDMA technologies.
The method for providing CDMA mobile communications was standardized in the United States by the Telecommunications Industry Association/Electronic Industries Association in TIA/EIA/IS-95-A entitled “Mobile Station-Base Station Compatibility Standard for Dual-Mode Wideband Spread Spectrum Cellular System,” referred to herein as IS-95. Combined AMPS & CDMA systems are described in TIA/EIA Standard IS-98. Other communications systems are described in the IMT-2000/UM, or International Mobile Telecommunications System 2000/Universal Mobile Telecommunications System, standards covering what are referred to as wideband CDMA (W-CDMA), CDMA2000 (such as CDMA2000 1xEV-DO standards, for example) or TD-SCDMA.
The Session Initiation Protocol (SIP) is a signaling protocol that can be used for call control, for example, of telephone conversations. To describe the switched communication connection, SIP uses the Session Description Protocol (SDP). When an SIP INVITE message is transmitted by an originating UE, a forking event may occur where a plurality of target terminals send provisional responses back to the originating UE, resulting in a plurality of “early” dialogs being instantiated before any of the dialogs are actually confirmed (e.g., based on a target user answering or accepting the call). In this case, it can be difficult for the originating UE to figure out how to handle the early dialogs.